As is known in the art, there are various applications where air is transported through a tube or pipe for sampling or measurement purposes. For example, an air quality or an environmental air parameter measurement system may have remotely located sensors instead of at the sensed environment. In addition, a sensor or a single set of multiple sensors may be used to sense a plurality of locations creating a measurement system known as a multi-location or a multipoint air sampling system. For one class of these systems, multiple tubes may be used to bring air samples from multiple locations to a centralized sensor(s). Centrally located air switches and/or solenoid valves may be used in this approach to sequentially switch the air from these locations through the different tubes to the sensor to measure the air from the multiple remote locations. These octopus-like systems sometimes known as star-configured or home run systems use considerable amounts of tubing. An example of such a star-configured system is described in U.S. Pat. No. 6,241,950, which is incorporated herein by reference. Other types of systems known to the art of air monitoring include those that are designed to monitor refrigerants and other toxic gases, which also are star-configured systems. Additionally, these types of star-configured systems have been used to monitor particulates in multiple areas such as clean room areas with a single particle counter. Generally, these types of systems, however, have historically not been applied to general air quality measurement applications, even though they could easily be adapted to do so.
Another multipoint sampling system known as a networked air sampling system uses a central ‘backbone’ tube with branches extending to various locations forming a bus-configured or tree like approach similar to the configuration of a data network. Air solenoids are typically remotely located proximate to the multiple sampling locations. Networked air sampling systems can also include remote and/or multiple-location air sampling through a tube or pipe for sampling locations in a building, outdoor air or ambient sampling, and sampling in smokestacks and exhaust air stacks. An exemplary networked air sampling system is described in U.S. Pat. No. 6,125,710, which is incorporated herein by reference.
The multipoint sampling systems which have been described may be applied to monitor a wide range of locations throughout a building, including any kinds of rooms, hallways, lobbies, interstitial spaces, penthouses, outdoor locations, and any number of locations within ductwork, plenums, and air handlers.
One characteristic of these multipoint sampling systems is that some parameters such as temperature in particular, but some other parameters as well such as ozone can not always be effectively measured from a remote location with a shared sensor. Furthermore, other parameters may be accurately measured at a remote location with a shared sensor but, for various reasons such as the need for more rapid sampling, may be preferred to be sensed locally at one or more of the sensed locations. In these situations, separate sensors and either distinct signal wires or a digital data communications network with cable, optical fiber or wireless links can be used to connect remote sensors such as temperature sensors to either the networked sampling system or possibly a building management system.
When these multipoint sampling systems are used to sample ductwork, plenums, air handlers or any other applications where flowing air in a partially contained area such as a duct or pipe is to be sampled and measured with a remote sensor, a tube or hollow duct probe must be inserted into the duct or partially contained space to withdraw a sample. Additionally however, a separate temperature or other parameter sensing probe or probes are needed to make whatever local sensor measurements are desired from these ducts or partially enclosed areas. The use of multiple separate probes for both sensing and drawing air samples leads to extra costs as well as more duct penetrations that unfavorably increase the installation expense of the multipoint sampling system.
As such this invention provides solutions to enable multipoint air monitoring systems to cost effectively and reliably monitor air parameters both locally and remotely within many of the partially confined locations within a building, and is especially suitable but not limited to applications involving monitoring air parameters within ductwork, plenums, and air handlers.